18-FDG-PET as a prognostic indicator in the treatment of aggressive Non-Hodgkin's Lymphoma-comparison with CT

18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Management of Aggressive Non-Hodgkin's B-Cell Lymphoma

18-Fluorodeoxyglucose (FDG-PET/CT) is an established imaging modality that has been proven to be of benefit in the management of aggressive B-cell non-Hodgkin's lymphoma, such as diffuse large B-cell lymphoma and advanced stage follicular lymphoma. The combination of anatomic and functional imaging afforded by FDG-PET/CT has led to superior sensitivity and specificity in the primary staging, restaging, and assessment of response to treatment of hematological malignancies when compared to FDG-PET and CT alone. The use of FDG-PET/CT for posttreatment surveillance imaging remains controversial, and further study is needed to ascertain whether this modality is cost effective and appropriate for use in this setting.

Diffuse large B cell lymphoma: how can we cure more patients in 2012?

Clinically this chapter will focus on 3 important issues critical in the management of diffuse large B cell lymphoma (DLBCL) in 2012: risk stratification, interim PET-CT scanning and the role of high dose therapy and ASCT in the rituximab era for patients with relapsed and primary refractory disease.

Interim [18F]fluorodeoxyglucose positron emission tomography scan in diffuse large B-cell lymphoma treated with anthracycline-based chemotherapy plus rituximab

PURPOSE

The prognostic value of [(18)F]fluorodeoxyglucose-positron emission tomography (PET), interpreted according to visual criteria, is a matter of debate for diffuse large B-cell lymphoma (DLBCL). Moreover, most published studies do not differentiate between patients treated with or without rituximab. We retrospectively investigated the prognostic value of PET performed in patients with DLBCL receiving chemotherapy plus rituximab. Images were interpreted both visually and by computing maximum standardized uptake value (SUV(max)) between PET performed at baseline and after two cycles of chemotherapy.

PATIENTS AND METHODS

One hundred twelve patients newly diagnosed with DLBCL were treated with an anthracycline-based regimen plus rituximab. A PET was performed after two cycles of treatment. PET positivity or negativity was related to progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier analysis.

RESULTS

Visual analysis showed that 70 patients (62.5%) presented with a negative PET scan after two cycles of treatment. The 3-year PFS and OS rates were 84% and 88%, respectively, in patients with PET-negative results versus 47% and 62%, respectively, in patients with PET-positive results (P < .0001 and P < .003, respectively). A second analysis was performed on 85 patients by using interim PET in a quantitative approach on the basis of a ΔSUV(max) evaluation of more than 66%. The 3-year PFS was 77% for patients with PET-negative results and 37.5% for patients with PET-positive results (P = .002).

CONCLUSION

An early PET scan after two cycles of treatment can effectively predict the outcome in patients with DLBCL treated with rituximab and anthracycline-based chemotherapy by using either a visual or quantitative approach.

Impact of FDG-PET/CT in the management of lymphoma

Since the introduction of (67)Gallium-citrate 30 years ago, nuclear medicine has played an important role in the evaluation of malignant lymphoma. During that time, several radiotracers were evaluated as potential alternatives for the diagnosis of lymphoma, but the introduction of (18)F-fluorodeoxyglucose PET (FDG-PET) marked a major turning point. FDG-PET took over most of the role of gallium, and is now an essential tool in the diagnosis of lymphoma. FDG-PET is increasingly being used for assessment of the tumor staging prior to treatment, for evaluating the response to treatment, and for monitoring the early reactions to therapy to predict the final outcome. FDG-PET has been shown to have more accurate diagnostic capability than conventional CT and MRI for distinguishing the tumor necrosis and residual masses frequently seen after therapy in lymphoma patients without any clinical and biochemical manifestation. Malignant lymphoma is the first disease for which FDG-PET was adopted as a tool for response assessment in the international standard criteria. However, lymphoma does not always display a clear high uptake, and there are some pitfalls in assessing the response to therapy. This review will highlight the most important applications of FDG-PET in lymphoma, focusing on the advantages and pitfalls of this imaging, and past and ongoing efforts to standardize the use of FDG-PET, particularly in response to assessment and therapy monitoring.

FDG-PET metabolic response predicts outcomes in anal cancer managed with chemoradiotherapy

Background:

The aim was to investigate the correlation between ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) metabolic response to chemoradiotherapy and clinical outcomes in squamous cell carcinoma (SCC) of the anus.

Methods:

A total of 48 patients with biopsy-proven anal SCC underwent FDG-PET scans at baseline and post chemoradiotherapy (54 Gy, concurrent 5-FU/mitomycin). Kaplan–Meier analysis was used to determine survival outcomes according to FDG-PET metabolic response.

Results:

In all, 79% patients (n=38) had a complete metabolic response (CMR) at all sites of disease, 15% (n=7) had a CMR in regional nodes but only partial response in the primary tumour (overall partial metabolic response (PMR)) and 6% (n=3) had progressive distant disease despite CMR locoregionally (overall no response (NR)). The 2-year progression-free survival (PFS) was 95% for patients with a CMR, 71% for PMR and 0% for NR (P<0.0001). The 5-year overall survival (OS) was 88% in CMR, 69% in PMR and 0% in NR (P<0.0001). Cox proportional hazards regression analyses for PFS and OS found significant associations for incomplete (PMR+NR) vs complete FDG-PET response to treatment only, (HR 4.1 (95% CI: 1.5–11.5, P=0.013) and 6.7 (95% CI: 2.1–21.6, P=0.002), respectively).

Conclusion:

FDG-PET metabolic response to chemoradiotherapy in anal cancer is significantly associated with PFS and OS, and in this cohort incomplete FDG-PET response was a stronger predictor than T or N stage.

The role of 18F-FDG PET/CT imaging in Waldenstrom macroglobulinemia

Disease assessment in WM is dependent on the quantification of the IgM monoclonal protein and percent involvement of the bone marrow. There is a need for imaging studies that objectively measure tumor load in these patients. In this study, we sought to examine the role of combined FDG-PET/CT imaging in the detection of tumor load and in the assessment of response to therapy. Thirty-five patients were enrolled on a prospective study using bortezomib and rituximab therapy and were included in this study because they completed a pre- and post-treatment FDG-PET/CT imaging at one facility (12 newly diagnosed and 23 relapsed/refractory). The use of combined FDG-PET/CT imaging showed positive findings in 83% of patients with WM, unlike prior studies using conventional imaging that indicate that only 20% of patients have lymphadenopathy or hepatosplenomegaly. Moreover, 43% of patients had abnormal bone marrow uptake on FDG-PET imaging that can potentially help in the assessment of their tumor load, especially with heterogenous sampling of the bone marrow. There was no statistical correlation between EORTC response criteria for FDG-PET/CT and response by monoclonal protein. This is the first study to examine the role of FDG-PET/CT imaging in WM. Future studies should examine the role of FDG-PET/CT in conjunction with monoclonal protein response in the assessment of progression-free survival in patients with WM.

18F-FDG PET/CT for early response assessment in diffuse large B-cell lymphoma: poor predictive value of international harmonization project interpretation

PET using (18)F-FDG has prognostic value when performed at the completion of initial chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL). (18)F-FDG PET may also be predictive of outcome when performed during the treatment course of DLBCL, but robust prospective studies and standardization of (18)F-FDG PET interpretation in this setting are lacking.

METHODS

In this prospective study, patients with advanced-stage DLBCL were treated with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy, and (18)F-FDG PET/CT was performed after cycle 2 or 3 and at the end of therapy. The (18)F-FDG PET/CT scans were interpreted according to the International Harmonization Project for Response Criteria in Lymphoma, and the maximum standardized uptake value (SUV) of the most (18)F-FDG-avid lesions was recorded.

RESULTS

Fifty patients were enrolled, and all underwent interim (18)F-FDG PET/CT. At a median follow-up of 33.9 mo, the positive predictive value (PPV) of interim (18)F-FDG PET/CT for relapse or progression was 42%, and the negative predictive value (NPV) was 77%. Interim (18)F-FDG PET/CT was significantly associated with event-free survival (P = 0.017) and with progression-free survival (P = 0.04) but not with overall survival (P = 0.08). End-of-therapy (18)F-FDG PET/CT had high PPV and NPV (71% and 80%, respectively) and was significantly associated with event-free survival, progression-free survival, and overall survival (P < 0.001). SUV measurements did not discriminate patients who relapsed or progressed from those who remained in remission.

CONCLUSION

When performed after 2 cycles of immunochemotherapy and interpreted according to International Harmonization Project criteria, early response assessment with PET/CT has a high NPV but low PPV in patients with advanced-stage DLBCL. Prospective trials are required to validate different criteria for the interpretation of interim (18)F-FDG PET/CT and establish the role of interim (18)F-FDG PET/CT in the management of patients with DLBCL.

Prognostic significance of interim ¹⁸F-FDG PET/CT after three or four cycles of R-CHOP chemotherapy in the treatment of diffuse large B-cell lymphoma

PURPOSE

(18)F-fluoro-2-dexoy-D-glucose-positron emission tomography (FDG-PET)/computerised tomography (CT) has been used for staging and monitoring responses to treatment in patients with diffuse large B cell lymphoma (DLBCL). The sequential interim PET/CT was prospectively investigated to determine whether it provided additional prognostic information and could be a positive predictable value within patients with the same international prognostic index (IPI) after the use of rituximab in DLBCL.

METHODS

One hundred and sixty-one patients with newly diagnosed DLBCL were enroled; the assessment of the PET/CT was performed at the time of diagnosis and mid-treatment of rituxibmab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP).

RESULTS

Sixty-seven patients (41.6%) presented with advanced stage disease and 27 (16.8%) had bulky lesions. Forty-three patients (26.7%) continued to have positive metabolic uptakes with a significantly high relapse rate (62.8%) compared to the patients with a negative interim PET/CT (12.1%) (P<0.01). After a median follow-up of 30.8months, the positivity of interim PET/CT was found to be a prognostic factor for both overall survival (OS) and progression-free survival (PFS), with a hazard ratio of 4.07 (2.62-6.32) and 5.46 (3.49-8.52), respectively. In the low-risk IPI group, the 3-year OS and PFS rates were significantly different in the patients with positive (53.3% and 52.5%) and negative (93.8% and 88.3%) interim PET/CT, respectively (P<0.01). These significant prognostic differences of interim PET/CT responses were consistent with the results of the patients with high-risk IPI group (P<0.01).

CONCLUSIONS

Interim PET/CT scanning had a significant predictive value for disease progression and survival of DLBCL in post-rituximab treatment; it might be the single most important determinant of clinical outcome in patients with the same IPI risk.

Surveillance computed tomography scans for patients with lymphoma: is the risk worth the benefits?

BACKGROUND

Concerns regarding the risks of cancer and cancer-related death as a result of radiation from computed tomography (CT) scans and the lack of data demonstrating a survival advantage for surveillance CT scans following lymphoma therapy have raised questions regarding their benefit. We compared the radiation-related lifetime cancer incidence (LCI) and mortality risks (LCMRs) associated with CT scans for staging and surveillance of non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) with the cumulative probability of lymphoma death (CPLD) during surveillance.

PATIENTS AND METHODS

The LCI and LCMR were calculated using published estimates of the cumulative organ-specific radiation doses from full-body CT scans and sex-, age-, and organ-dependent cancer risks per 0.1 Gy provided by the Biologic Effects of Ionizing Radiations VII report. Surveillance, Epidemiology, and End Results (SEER) data were used to identify cases between 2000 and 2006 from 17 SEER registries and calculate CPLD for specified cohorts.

RESULTS

For a 70-year-old patient, a single full-body CT examination is associated with a LCI of 0.044% and 0.057%, and a LCMR of 0.032% and 0.044% for males and females, respectively. For 20-year-old patients the LCMRs were 0.071% for men and 0.108% for women. The LCI and LCMR were lower for males and were markedly less than the CPLD at 5 years for most lymphoma subtypes, but relevant for younger women with HL.

CONCLUSION

Although the LCMR from CT scans is small compared with lymphoma-related deaths for most subgroups, these data should be discussed with patients in formulating plans for surveillance following lymphoma therapy.

PET-CT Imaging of Lymphoma

PET-CT is now the mainstay for imaging lymphoma patients. The complimentary nature of the metabolic and anatomic information provided by a PET-CT examination has become an essential component of patient management, complimenting clinical and laboratory criteria used in staging, restaging, and therapy monitoring. The nature of a particular lymphoma subtype and the patient’s clinical presentation will determine the extent PET-CT imaging is best employed in a particular patient’s management.

FDG-PET/CT in lymphoma

Molecular Imaging has played a prominent role in the assessment of lymphoma for now almost three decades since the introduction of (67)Ga-citrate imaging for staging and restaging of both Hodgkin's and non-Hodgkin's lymphoma (HL and NHL). Since then other molecular probes have been investigated for more accurate pre- and posttreatment assessment of lymphomas but none of these probes was widely accepted and utilized until the emergence of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). FDG-PET or FDG-PET/CT, which combines FDG-PET with CT scanning, is now widely utilized for response assessment of lymphoma after completion of therapy, for pretreatment staging, and, increasingly, also for assessment of response during therapy (therapy monitoring). Particularly for response assessment at therapy conclusion, FDG-PET has been shown to be considerably more accurate than CT or conventional MRI because of its ability to distinguish between viable tumor and necrosis or fibrosis in posttherapy residual mass (es) that are frequently present in patients with lymphoma without any other clinical or biochemical evidence of disease. FDG-PET/CT is therefore the noninvasive modality of choice for response classifications of HL and aggressive NHLs consistent with the recently revised, primarily FDG-PET/CT-based, response criteria for lymphoma. This review will highlight the most important applications of FDG-PET (FDG-PET/CT) in lymphoma emphasizing the strengths and pitfalls of this imaging approach, past and ongoing efforts to standardize the use of FDG-PET, particularly in response assessment and therapy monitoring. Other promising molecular probes for lymphoma imaging will also be briefly discussed.

Midtreatment 18F-fluorodeoxyglucose positron-emission tomography in aggressive non-Hodgkin lymphoma

BACKGROUND

The use of (18) F-fluorodeoxyglucose positron-emission tomography (PET) scan has increased considerably in the clinical management of non-Hodgkin lymphoma patients, and its role as a prognostic factor during chemotherapy has been established recently.

METHODS

Between May 2003 and May 2009, 91 newly diagnosed patients with primary mediastinal large B-cell lymphoma (PMLBCL) and diffuse large B-cell lymphoma (DLBCL) were treated with 12 weekly cycles of rituximab-MACOP-B (n = 12 patients with PMLBCL), 6 cycles of rituximab-CHOP21 (n = 65 patients with DLBCL, aged < 60 years and 1 patient with PMLBCL), or 8 weekly cycles of rituximab-VNCOP-B (n = 13 DLBCL patients, aged ≥ 60 years). All patients underwent a staging PET examination at baseline and a midtreatment (interim) PET examination after 6 weeks of rituximab-MACOP-B treatment, 3 cycles of rituximab-CHOP21 treatment, or 4 weeks of rituximab-VNCOP-B treatment and again at the end of the chemo-immunotherapy regimen.

RESULTS

At midtreatment evaluation, 35 patients showed a persistently positive PET scan; only 6 (17%) of these patients achieved a continuous complete response (CCR). However, 56 patients presented with a negative interim PET, and 50 (89%) of these patients achieved and maintained a CCR. Comparison between the 2 PET groups indicated a statistically significant association between PET findings and event-free survival (P = .0001) and overall survival (P = .0001).

CONCLUSIONS

The results of this study indicated that midtreatment PET may represent a significant step forward in helping physicians make crucial decisions on further treatment. Cancer 2011. © 2010 American Cancer Society.

18F-fluorodeoxyglucose-positron emission tomography before, during and after treatment in mature T/NK lymphomas: a study from the GOELAMS group

BACKGROUND

In non-cutaneous T-cell/natural killer (T/NK) lymphomas, the prognostic value of (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) during or after therapy is unknown.

PATIENTS AND METHODS

In this retrospective study, 54 T/NK lymphoma patients were assessed using FDG-PET before (n = 40), during (n = 44) and/or after therapy (n = 31).

RESULTS

FDG-PET showed an abnormal FDG uptake in all cases. Interim FDG-PET was negative in 25 of 44 cases. After completion of therapy, 19 of 31 patients reached complete remission with negative FDG-PET. In ALK+ anaplastic large cell lymphomas, the 4-year progression-free survival (PFS) was 80% and the negative predictive value of post-therapy FDG-PET was 83% (n = 9). In ALK- T/NK lymphomas, the 4-year PFS was 59% for patients with a negative interim FDG-PET versus 46% for patients with a positive interim FDG-PET (P = 0.28, n = 35). Similarly, there was no statistical difference in 4-year PFS between negative and positive post-therapy FDG-PET in these lymphomas (51% and 67%, respectively, P = 0.96). The 4-year cumulative incidence of relapse from a negative post-therapy FDG-PET was 53% in ALK- T/NK lymphomas.

CONCLUSIONS

Although T/NK lymphomas are FDG-avid at diagnosis, a negative interim or post-therapy FDG-PET does not translate into an improved PFS in ALK- T/NK lymphomas.

Personalized versus evidence-based medicine with PET-based imaging

In this Perspective the feasibility, scope and impact of integrating PET-based personalized medicine into the evidence-based clinical practice of oncology is discussed. The basic concepts of 'evidence-based medicine' and 'personalized medicine' at times seem contradictory; however, I will discuss, with specific clinical situations as examples, a synergistic and probably incremental link between the two and propose that the result of such integration will ultimately improve patient management. Tailoring therapeutic approaches and regimens by molecular imaging, with PET at its forefront, would enable disease management at the individual level and this modification would hopefully further strengthen the evidence-based approach in oncology.

Interim fluorodeoxyglucose positron emission tomography for early response assessment in diffuse large B cell lymphoma: where are we now?

Fluorodeoxyglucose (FDG)-positron emission tomography (PET) has been established in response assessment after treatment of diffuse large B cell lymphoma (DLBCL) and has been incorporated in the International Workshop Criteria (IWC). Early response assessment is increasingly being used in trials and clinical practice with the hope that it has a greater power to discriminate between good and poor prognosis patients at an earlier point in time. Early data have been very promising and suggest that PET after two to three cycles predicts progression-free survival with high accuracy. Early prediction of prognosis has the potential of enabling early treatment tailoring according to the individual prognosis. Studies are yet to be done to examine the effect of changing therapy early on the basis of poor metabolic response. However, the prognosis of responders/non-responders has been different in various studies, with few recent studies casting some doubt on the value of interim PET. Some of these differences are due to variability in patient populations and treatment protocols. However, there are also important factors related to the methodology of PET scanning and the criteria used to assess response. There is a need for a consensus on a uniform methodology for the use of interim PET both in clinical trials and routine clinical practice. This article critically reviews the current status and suggests future questions for further research.

Tumor Burden Assessed by the Maximum Standardized Uptake Value and Greatest Diameter on FDG-PET Predicts Prognosis in Untreated Diffuse Large B-cell Lymphoma

PURPOSE

It is uncertain whether the tumor burden as assessed using FDG-PET has prognostic significance in newly diagnosed diffuse large B-cell lymphoma (DLBCL). The authors undertook this study to determine whether a parameter that reflects both FDG uptake magnitude and the greatest tumor diameter is a prognostic indicator in DLBCL.

MATERIALS AND METHODS

Forty-two DLBCL patients (age, 57.4 ± 15.5 years; male/female = 25/17; stage I/II/III/IV=5/17/10/10) who underwent FDG-PET before chemotherapy were enrolled. A lesion with the highest maximum standardized uptake value (MaxSUV) on the PET image was selected, and size-incorporated MaxSUV (SIMaxSUV) of mass was calculated as MaxSUV × greatest diameter (mm) on the transaxial PET image. Median follow-up duration was 20.0 months.

RESULTS

Twelve (28.6% = 12/42) patients experienced disease progression, and 10 (23.8% = 10/42) died during follow-up. Among six variables [Ann Arbor stage, %Ki-67 expression, International Prognostic Index (IPI), MaxSUV, greatest diameter, and SIMaxSUV] investigated, only SIMaxSUV was found to be a single determinant of progression-free and overall survivals by multivariate analyses (p < 0.05).

CONCLUSION

These results suggest that SIMaxSUV, a new FDG-PET parameter that incorporates FDG uptake magnitude and the greatest tumor diameter, may be a useful indicator of prognosis in untreated DLBCL.

Cost effectiveness of positron emission tomography in patients with Hodgkin's lymphoma in unconfirmed complete remission or partial remission after first-line therapy

PURPOSE

To assess the cost effectiveness of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with Hodgkin's lymphoma (HL) with unconfirmed complete remission (CRu) or partial remission (PR) after first-line treatment.

PATIENTS AND METHODS

One hundred thirty patients with HL were prospectively studied. After treatment, all patients with CRu/PR were evaluated with FDG-PET. In addition, PET-negative patients were evaluated with standard follow-up, and PET-positive patients were evaluated with biopsies of the positive lesions. Local unit costs of procedures and tests were evaluated. Cost effectiveness was determined by evaluating projected annual economic impact of strategies without and with FDG-PET on HL management.

RESULTS

After treatment, CRu/PR was observed in 50 (40.0%) of the 127 patients; the sensitivity, specificity, and positive and negative predictive values of FDG-PET were 100%, 92.0%, 92.3%, and 100%, respectively (accuracy of 95.9%). Local restaging costs without PET were $350,050 compared with $283,262 with PET, a 19% decrease. The incremental cost-effectiveness ratio is -$3,268 to detect one true case. PET costs represented 1% of total costs of HL treatment. Simulated costs in the 974 patients registered in the 2008 Brazilian public health care database showed that the strategy including restaging PET would have a total program cost of $56,498,314, which is $516,942 less than without restaging PET, resulting in a 1% cost saving.

CONCLUSION

FDG-PET demonstrated 95.9% accuracy in restaging for patients with HL with CRu/PR after first-line therapy. Given the observed probabilities, FDG-PET is highly cost effective and would reduce costs for the public health care program in Brazil.

Clinical significance of diffusely increased splenic uptake on FDG-PET

Diffusely increased uptake is more commonly observed than focal uptake in the spleen on a whole-body [F] fluorodeoxyglucose-positron emission tomography/computed tomography. The significance of diffusely increased splenic uptake varies in different clinical settings. On a pre-therapeutic scan for lymphoma, splenic uptake, greater than hepatic uptake, is a relative reliable indication of lymphomatous involvement of the spleen, unless the patient has a history of recent cytokine administration. In HIV infection, increased splenic uptake is usually noted in the early stage of the disease, which could reflect massive stimulation of B-cells in the spleen by nonreplicating antigenic material. Diffusely increased splenic uptake may also be present in sarcoidosis, malaria, and many inflammatory or hematopoietic diseases. Therapeutic-related reactive splenic uptake concurrent with bone marrow uptake is often secondary to administration of granulocyte colony-stimulating factor for myelosuppression or high-dose interferon-alpha-2b adjuvant therapy for melanoma.

PET and PET/CT for response evaluation in lymphoma: Current practice and developments

Positron emission tomography (PET) using the radiolabelled glucose analog 2-[18F]fluoro-2-deoxy-d-glucose (FDG) is increasingly used for response assessment in patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). These patients often present with a residual mass after therapy, but only a minority will relapse as most of these masses consist of inactive fibrosis. However, some patients have residual disease after first-line treatment and they can benefit from additional or early salvage therapy. Special interest for early, but accurate, assessment of response is growing accordingly. Conventional radiological techniques cannot differentiate between active tumoural tissue and fibrosis in these masses. In contrast, FDG-PET has the ability to differentiate between viable tumour and fibrosis and has been evaluated as an initial staging tool, for response assessment after completion of therapy and as a prognostic marker early during treatment. In this review, we will focus especially on the value of PET for response assessment.

Aggressive and indolent non-Hodgkin's lymphoma: Response assessment by Integrated International Workshop Criteria

Until recently, response assessment in patients with lymphoma was primarily performed by computed tomography (CT). Based on CT, International Workshop Criteria (IWC) were developed and widely used. Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) is a more sensitive and specific imaging technique for the detection of residual disease in lymphoma, and Revised Integrated International Workshop Criteria (IWC + PET) were recently proposed by the members of the International Harmonization Project (IHP), which combine both imaging techniques. We determined whether these new IWC + PET-criteria, can more accurately predict outcome compared to IWC-criteria in aggressive and indolent non-Hodgkin's lymphoma (NHL), and therefore correlated IWC and IWC + PET response with time-to-next-treatment (TNT) in 69 patients with NHL. We demonstrated that IWC + PET-guidelines are highly recommended over IWC-guidelines for patients with potentially-curable and routinely FDG-avid lymphoma. In contrast, no additional value of IWC + PET was demonstrated in a small group of patients with incurable histological subtypes.

Discordant response to chemotherapy: An unusual patternof fluoro-deoxy-d-glucose uptake in heavily pre-treated lymphoma patients

In recent years a number of studies have been published showing strong value of positron emission tomography using 18-Fluorine 2-fluoro-deoxy-D-glucose (FDG-PET) in term of diagnosis, response to treatment, disease recurrence and prognostic indicator in early restaging. This study observed 17 patients who presented contemporary disease progression in some localizations as well as regression in others (PROG + REG pattern); this investigation assessed that this unusual pattern of FDG uptake lead to an unfavorable prognosis. Among 1280 FDG-PET scans performed between August 2003 and December 2004 on patients affected by lymphoma with suspected recurrence, attention was focused on 17 patients presenting a PROG + REG pattern. At follow-up (4 months) only 1/17 (6%) patient was in complete remission after salvage therapy, while 6/17 (35%) had stable disease and 10/17 (59%) had rapid progression of the disease. This study further strengthens the role of FDG-PET in lymphoma patients follow-up, as it can provide useful information to better differentiate those cases who may benefit from conventional treatments from others in whom additional treatment would provide avoidable toxicity.

Functional diagnosis of residual lymphomas after radiochemotherapy with positron emission tomography comparing FDG- and FLT-PET

Positron emission tomography (PET) using 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) is used as a functional imaging technique for the staging and follow-up of lymphomas. However, additional information about the tumor proliferation rate using 3'-deoxy-3'-[(18)F]fluorothymidine (FLT) may be useful for the assessment of prognosis. We enrolled 48 patients with Hodgkin's (n = 15) and non-Hodgkin's lymphoma (n = 33) with residual masses >2 cm examined by tracer studies with FDG and FLT. The results were related to median overall and progression-free survival. In 15 out of 48 patients analysed using FDG, positive results were found. Using FLT, 10 out of 48 patients were positive. 33 patients were FDG negative. Eight patients were positive both using FDG and FLT. Overall survival for patients with a negative PET scan was significantly higher than for patients with positive PET, irrespective of the tracer used. FLT alone was able to discriminate between patients with long or short overall survival. However, there was no statistical significance comparing FDG/FLT negative versus FDG negative alone. Although FDG detected more lesions than did FLT, the additional biological characterization of tumor tissue with respect to proliferation by FLT might be useful by providing complementary information for the identification of recurrence. However, the present data show no advantage of combined FDG/FLT studies over FDG alone with respect to the prediction of survival.

Hodgkin lymphoma: Response assessment by Revised International Workshop Criteria

Until recently, response assessment in patients with Hodgkin's lymphoma (HL) was primarily performed by computed tomography (CT). Based on CT, International Workshop Criteria (IWC) were developed and widely used. Fluorodeoxyglucose positron emission tomography (FDG-PET) has a higher sensitivity and specificity compared with that of CT, and Revised International Workshop Criteria (IWC + PET) were recently proposed, which combine both imaging techniques. We determined whether these integrated IWC + PET-criteria can more accurately predict outcome compared with IWC-criteria in 56 patients with HL. Of the original 56 patients, nine patients relapsed and 47 are still in remission after a median follow-up of 9 years. Based on IWC-criteria, 15 patients had a complete remission (CR) after chemotherapy, 20 had complete remission unconfirmed (CRu), 19 had partial remission (PR) and two had stable disease (SD). In comparison, by IWC + PET, 47 had CR, seven had PR and two had SD. For IWC, outcome was not significantly different in patients with CR/CRu compared to PR (P = 0.61), while for IWC + PET criteria, time-to-next-treatment was significantly shorter in patients with PR compared to CR (P = 0.01). Therefore, IWC + PET-guidelines provide a more accurate response classification compared with that of IWC-guidelines, and are the preferred method for response assessment in patients with Hodgkin's lymphoma.

PET imaging in lymphoma

PET has become a cornerstone procedure in modern lymphoma management. This paper reviews, from a clinical point of view, the evidence for using PET in the different subtypes of lymphoma and the different steps of their management. The reader is given an overview of the current PET-based interventional lymphoma trials and an insight into possible future developments in the field, including new PET tracers.

Management of lymphoma in pregnancy

One in every thousand pregnancies is complicated by a concurrent diagnosis of cancer. Lymphoma is currently the fourth most common malignancy diagnosed during pregnancy and its incidence is rising. The diagnosis and management of any malignancy during pregnancy is clearly a clinical and emotional minefield for both patients and health-care professionals. The major challenge is to optimize medical treatment offered to the mother, while limiting the impact on the fetus. Given the relative rarity of the situation, current practice is guided by case reports and personal experience of management of similar patients. Our centre has a large and busy lymphoma practice, and has cared for several women diagnosed with a variety of subtypes of lymphoma over the years. This review aims to summarize current opinion about best practice regarding these patients and discusses options available from the current literature.

Role of [18F]Fluorodeoxyglucose Positron Emission Tomography Scan in the Follow-Up of Lymphoma

Purpose

In lymphoma, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) is routinely used for initial staging, early evaluation of treatment response, and identification of disease relapse. However, there are no prospective studies investigating the value of serial FDG-PET over time in patients in complete remission.

Patients and Methods

All patients with lymphoma who achieved the first complete remission were prospectively enrolled onto the study and scheduled for serial FDG-PET scans at 6, 12, 18, and 24 months; further scans were then carried out on an annual basis. Overall, the population included 421 patients (160 patients with Hodgkin's lymphoma [HL], 183 patients with aggressive non-Hodgkin's lymphoma [NHL], and 78 patients with indolent follicular NHL). All patients had a regular follow-up evaluation, including complete clinical and laboratory evaluation, and final assessment of any suspect FDG-PET findings using other imaging procedures (computed tomography [CT] scan) and/or biopsy and/or clinical evolution. FDG-PET findings were reported as positive for relapse, inconclusive (when equivocal), or negative for relapse.

Results

PET enabled documentation of lymphoma relapse in 41 cases at 6 months, in 30 cases at 12 months, in 26 cases at 18 months, in 10 cases at 24 months, and in 11 cases at more than 36 months. All 36 patients with inconclusive positive PET underwent biopsy; only 12 (33%) of 36 patients had a concomitant suggestion of positivity on CT. A lymphoma relapse was diagnosed in 24 (66%) of 36 patients.

Conclusion

Our results confirm FDG-PET as a valid tool for follow-up of patients with HL and NHL. In patients with inconclusive positive results, histologic confirmation plays an important role in identifying true relapse.

Pretransplantation positron emission tomography scan is the main predictor of autologous stem cell transplantation outcome in aggressive B-cell non-Hodgkin lymphoma

BACKGROUND

Limited data exist about the role of second-line chemotherapy response assessed by positron emission tomography (PET) as a prognostic factor in patients with aggressive non-Hodgkin Lymphoma (NHL) who undergo autologous stem cell transplantation (ASCT). The objective of this analysis was to investigate the main determinants of prognosis in patients with aggressive B-cell NHL who undergo ASCT, focusing on the impact of pretransplantation PET, secondary age-adjusted International Prognostic Index (sAA-IPI) score, histology, and previous response to first-line chemotherapy.

METHODS

Seventy-five patients with diffuse, large B-cell lymphoma or grade 3 follicular lymphoma who were treated at the author' institution with second-line chemotherapy (combined ifosfamide, etoposide, and epirubicin [IEV]) followed by ASCT between September 2002 and September 2006 were included. All patients were evaluated by PET after 1 to 3 courses of IEV chemotherapy before ASCT, and all patients received a conditioning regimen of combined carmustine, etoposide, cytosine arabinoside, and melphalan. The prognostic impact of pretransplantation PET, sAA-IPI score, histology, and previous response to first-line chemotherapy was evaluated by univariate and multivariate analyses.

RESULTS

Seventy-two of 75 patients underwent ASCT. In a univariate analysis for progression-free survival (PFS) and overall survival (OS), a significant association was observed with pretransplantation PET (PFS, P< .00001; OS, P< .01) and previous first-line response (PFS, P= .02; OS, P= .04). In the multivariate framework, pretransplantation PET was identified as the only independent prognostic factor (PFS, P< .001; OS, P= .01).

CONCLUSIONS

The current data indicated that pretransplantation PET is the main prognostic predictor in patients with aggressive B-cell NHL who are scheduled for ASCT.

High incidence of false-positive PET scans in patients with aggressive non-Hodgkin's lymphoma treated with rituximab-containing regimens

BACKGROUND

Positron emission tomography (PET) is a powerful predictor of relapse and survival in non-Hodgkin's lymphomas (NHLs) based on studies carried out in the prerituximab era. Little is known about the predictive power of PET in rituximab-treated patients.

PATIENTS AND METHODS

Patients with aggressive B-cell NHL with baseline and follow-up PET studies were included. Clinical characteristics, PET and computed tomography scans, biopsy results, and outcomes were reviewed. PET was defined as positive if higher than mediastinal or background activity was observed.

RESULTS

In all, 51 patients (diffuse large B cell-38; mantle cell lymphoma-13) treated with rituximab-containing regimens were included. For 13 of 40 patients (32.5%), mid-therapy PET studies were positive and 9 of 48 patients (18.7%) had positive posttherapy PET. The positive predictive value (PPV), negative predictive value (NPV), sensitivity (Se), and specificity (Sp) of the mid-therapy PET for predicting relapse were 33% [95% confidence interval (CI) 19% to 49%], 68% (95% CI 51% to 81%), 33% (95% CI 6% to 76%), and 68% (95% CI 49% to 82%), respectively. For posttherapy PET, the relapse PPV, NPV, Se and Sp were 19% (95% CI 9% to 33%), 81% (95% CI 67% to 91%), 13% (95% CI 0.6% to 53%), and 80%(95% CI 64% to 90%), respectively.

CONCLUSIONS

Compared with previous reports in prerituximab era, addition of rituximab resulted in reduced PPV and sensitivity of mid- and posttherapy PET in patients with aggressive B-cell NHL.

Therapeutic evaluation and prognostic value of interim hybrid PET/CT with (18)F-FDG after three to four cycles of chemotherapy in non-Hodgkin's lymphoma

PURPOSE

Modern risk-adapted treatment requires accurate assessment of the patient's prognosis. This study assessed the value of hybrid PET/CT with 2-[18F]fluoro-2-deoxy-d-glucose ((18)F-FDG) after 3-4 cycles of chemotherapy for early evaluation of response to therapy and prediction of progression-free survival (PFS) in non-Hodgkin's lymphoma (NHL).

METHODS

Sixty-one consecutive NHL patients (37 male and 24 female) were included. The (18)F-FDG hybrid PET/CT scans were performed prior to chemotherapy (initial scan) and after 3-4 cycles of chemotherapy (interim scan). Interim FDG findings were correlated to the PFS using Kaplan-Meier analysis. Regression analyses were employed to test for independence of established pretreatment prognostic factors.

RESULTS

After 3-4 cycles of chemotherapy, positive (18)F-FDG lesions were found in 28 patients, minimal residual uptake (MRU) in 8 and negative scans in 25 patients. In FDG-positive group, 22 patients showed progress and three died. Nine (18)F-FDG-negative patients and 4 patients from the MRU group relapsed. Survival analyses showed highly significant associations between early interim FDG imaging and PFS (P < 0.0005). The 2-year PFS rate for FDG-negative patients was 72.2 and 23.0% for FDG-positive patients. The regression model showed that the predictive value of FDG imaging owed its significance to the very high hazard ratio between patients with positive FDG imaging and patients with negative FDG imaging (P < 0.001).

CONCLUSIONS

Early interim FDG imaging is an excellent and independent predictor of PFS in NHL. An early assessment of chemotherapy response with FDG scans may provide useful information for selection of patients for alternative therapeutic strategies.

The value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography in extranodal natural killer/T-cell lymphoma

PURPOSE

To our knowledge, there are no published data pertinent to the use of [(18F)]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with natural killer (NK)/T-cell lymphoma. The purpose of this study was to assess the value of FDG PET/CT in this aggressive type of non-Hodgkin lymphoma.

PATIENTS AND METHODS

All patients with NK/T-cell lymphoma referred for FDG PET/CT at our institution from July 2001 to July 2006 were retrospectively studied. PET/CT examinations were blindly reviewed by 2 experienced readers. The results were compared with the status of the disease, which was determined after evaluation of biopsy, laboratory, clinical and conventional imaging examination, and follow-up results. PET/CT results were thereby classified as true-positive, true-negative, false-positive, or false-negative. The degree of FDG uptake in the positive lesions was semiquantified using maximum standard uptake value (SUV(max)).

RESULTS

Twenty-one PET/CT examinations were performed in 10 patients with NK/T-cell lymphoma. For nasal disease, PET/CT was true-positive in 5 cases, true-negative in 15 cases, and positive but unconfirmed in 1 case. For extranasal disease, PET/CT was true-positive in 3 cases, true-negative in 16 cases, and false-negative in 2 cases. The mean SUV(max) in PET-positive lesions in nasal cavities or paranasal sinuses was 16 gm/mL (range, 5-25 gm/mL; median, 19.3 gm/mL). In extranasal disease, the mean SUV(max) was 10.9 gm/mL (range, 4.6-34.1 gm/mL; median, 5.6 gm/mL).

CONCLUSION

Viable NK/T-cell lymphoma is intensely FDG hypermetabolic. PET/CT appears to be sensitive for the detection of disease in the nasopharynx and, to a lesser extent, in extranasal sites.

Mucosa-associated lymphoid tissue lymphoma studied with FDG-PET: a comparison with CT and endoscopic findings

OBJECTIVE

We investigated the accumulation of 2-deoxy-2-[(18)F] fluoro-D: -glucose positron emission tomography (FDG-PET) in patients with mucosa-associated lymphoid tissue (MALT) lymphoma patients as compared with computerized tomography (CT) and endoscopic imaging.

METHODS

FDG-PET was performed on 13 untreated patients with MALT lymphoma. CT scanning of the affected areas was performed in all the patients to compare with the FDG-PET images. In five patients with gastric MALT lymphoma, comparison was also made with the endoscopic findings.

RESULTS

Of the 13 untreated MALT lymphoma patients, all 8 non-gastric MALT lymphoma patients exhibited abnormal accumulation of FDG. However, in the five gastric MALT lymphoma patients, no abnormal FDG accumulation was observed. Although lesions could be confirmed on CT images from the patients other than those with gastric MALT lymphoma, the mucosal lesions of gastric MALT lymphoma could be observed only by endoscopy.

CONCLUSIONS

FDG-PET can be used to detect MALT lymphoma when it forms mass lesions, whereas it is difficult to detect non-massive MALT lymphoma of gastrointestinal origin.

FDG PET and risk-adapted therapy in Hodgkin's and non-Hodgkin's lymphoma

PURPOSE OF REVIEW

The prognostic utility of midtreatment fluorine-18 fluorodeoxyglucose positron emission tomography (F-FDG PET) has become widely appreciated in aggressive B-cell non-Hodgkin's lymphoma and, more recently, in Hodgkin's lymphoma. Outcomes based on midtreatment FDG PET performed during primary and salvage therapy are reviewed and management strategies considered, with a focus on treatment intensification for poor-risk disease as identified by metabolic imaging.

RECENT FINDINGS

PET, when performed after as few as two cycles of primary chemotherapy, is strongly prognostic in certain aggressive lymphomas and provides information independently from validated prognostic indices. What constitutes a positive or negative scan is not always clear, particularly if there is minimal tracer uptake, and the causes of false positive and false negative scans must be considered. How to tailor therapy based on the midtreatment PET result is the focus of current trials and is presently being defined for both Hodgkin's and non-Hodgkin's lymphoma.

SUMMARY

Early PET has the strong potential to improve clinical outcomes by sparing good-risk patients from overly aggressive treatments, and by more accurately identifying poor-risk patients so as to guide changes in management. Treatment modifications on the basis of midtreatment PET are presently best made in clinical trial settings.

Non-Hodgkin lymphoma: retrospective study on the cost-effectiveness of early treatment response assessment by FDG-PET

PURPOSE

Although lymphomas are very chemosensitive, 50% of patients with aggressive non-Hodgkin lymphoma (NHL) are not cured with standard first-line treatment. This consists of six cycles of doxorubicin, vincristine, prednisolone and cyclophosphamide (CHOP), recently complemented with rituximab. Preliminary studies show that PET mid-treatment is a good predictor of the remission status at the end of therapy. As patients with persistent FDG uptake after three cycles are unlikely to gain a complete remission, the remaining three cycles of chemotherapy are useless. We investigated the costs and benefits for the use of PET in this early treatment setting.

METHODS

We conceived a model using a conventional arm where patients receive the full regimen of six cycles of CHOP [-rituximab] and an experimental algorithm where patients receive either six cycles (PET response) or only three cycles (PET non-response). Based on a patient sample (2004-2006), we calculated the costs for hospitalisation and treatment. We took into account all costs accrued (including overhead costs). We used a sensitivity analysis by varying the most important parameters.

RESULTS

With a PET price of 700 euro and CHOP price (per cycle) of 1,829 euro , we can conclude to cost saving of 1,879 euro per patient. The PET price can increase up to 2,580 euro and the cost for one cycle of CHOP can decrease to 500 euro per cycle before cost savings are nil. The percentage of non-responders may be as low as 10%. The implementation of rituximab in first-line therapy only increases benefit (4,900 euro/pt).

CONCLUSION

We conclude to substantial cost savings if management of NHL patients is based on mid-treatment PET scan. The economical data we used seem to be comparable to those published in other European studies. Implementation of Mabthera in first line only increases cost savings.